Magnetically Induced Anisotropic Microstructures on Polyethylene Glycol Hydrogel Facilitate BMSC Alignment and Osteogenic Differentiation.

Many tissues exhibit structural anisotropy, which imparts orientation-specific properties and functions. However, recapitulating the cellular patterns found in anisotropic tissues presents a remarkable challenge, particularly when using soft and wet hydrogels. Herein, we develop self-assembled anisotropic magnetic Fe(3)O(4) micropatterns on polyethylene glycol hydrogels utilizing dipole-dipole interactions. Under the influence of a static magnetic field, Fe(3)O(4) nanoparticles align into highly ordered structures with a height of 400-600 nm and a width of 8-10 μm. Furthermore, our layer-by-layer assembly technique enables the creation of oriented micropatterns with varying densities and heights, which can be further manipulated to form three-dimensional structures by adjusting the angle of the magnetic field. These anisotropic magnetic Fe(3)O(4) micropatterns can be applied to various substrates, including treated glass slides, standard glass slides, silicon wafers, and polydimethylsiloxane. The patterned Fe(3)O(4) scaffolds, modified with gold coating, effectively enhance cellular adhesion, orientation, and osteogenic differentiation of bone marrow-derived stem cells, which is crucial for effective tissue repair. Overall, this study presents an efficient strategy for constructing anisotropic Fe(3)O(4) micropattern hydrogels, providing a bioactive platform that significantly enhances cellular functions.